The company’s new mid-tier model, the successor to Sonnet 4.6, can “make plans, use tools like browsers and terminals, and run autonomously at a level that, just a few months ago, required larger and more expensive models,” Anthropic wrote in a release, adding that its performance “is close to that of Opus 4.8.” The company was also careful to include that it has a “much lower ability to perform dangerous cybersecurity tasks than our current Opus models.”